StagnantStandards Track: Core
Created: 2018-11-01
trustfarm <trustfarm.info@gmail.com>, trustfarm <cpplover@trustfarm.net>
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1 min read

EIP-1485 proposes a new version of the Ethash algorithm, called TEthashV1, which is designed to be more ASIC-resistant and improve the security of the Ethereum network. The proposal includes changes to the algorithm's mix function, which is used to generate the final hash, as well as adjustments to the DAG size and epoch length. The goal is to make it more difficult and expensive for ASICs to mine Ethereum, which would help to decentralize the network and prevent a single entity from controlling a significant portion of the hash rate. The proposal also includes a transition plan to gradually phase in the new algorithm and ensure a smooth upgrade process for miners and other stakeholders. Overall, EIP-1485 aims to improve the long-term sustainability and security of the Ethereum network by making it more resistant to centralization and attacks.

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Simple Summary

This EIP modifies ethash in order to break ASIC miners specialized for the current ethash mining algorithm.


This EIP pursue "obsolete current ASIC miners" by modifying PoW algorithm in a very low risk manner and update to latest hash algorithm from deprecated FNV Hash algorithms.

Following TEthashV1 algorithm suggests safe transition of PoW algorithms and secure the FNV Algorithm in MIX Parts.


Provide original Ethash proof of work verification with minimal set of changes by updating FNV0 algorithm


1. Reference materials on ETHASH FNV0

Where FNV Applied on ETHASH

  • In ETHASH , FNV Hash is used on

      1. On data aggregation function, MIX parts.
    • Ethash Algorithm
      Header + Nonce
        **[MIX 0]**  --> **[DAG Page]**
             |               |
           Mixing         <--|
        **[Mix 63]**
             |-----> Mix64  [Process] ---> Mix Digest [32B]
    • FNV used in DAG Generation and Mixing for random access or DAG Page.

2. Current applied Ethash FNV hash implementation is deprecated now.

FNV-0_hash (deprecated)

It is a simple way of hashing algorithm

 hash = 0
 for each byte_of_data to be hashed
 	hash = hash × FNV_prime
 	hash = hash XOR octet_of_data
 return hash

When analysed FNV-0 , there's very weak avalanche effect, when hash input changes on 1~2bits. refer FNV-Analysis reference section

We need to research and apply newer FNV hash or short message hash algorithm.

3. FNV1A hash algorithm description

Previous proposed algorithm based on FNV1 EIP-1355

There's a implementation that looks like "Missing Offset Bias" at FNV1A.

Quotation of original algorithm FNV1A

use hash offset
FNV-1a hash
The FNV-1a hash differs from the FNV-1 hash by only the order in which the multiply and XOR is performed:[8][10]

   hash = FNV_offset_basis
   for each byte_of_data to be hashed
   	hash = hash XOR byte_of_data
   	hash = hash × FNV_prime
   return hash

FNV_offset_basis and computation order change of xor and multiplication Makes one more xor and multiply computation, but more secure hash effects than FNV0. and make dispersion boundary condition (0, even number, ..) by using of Prime Number.

4. Real Implementation for FNV1A

Consider real computation resources, in TEthashV1 uses hash byte_of_data to 4bytes aligned data.

In TETHashV1, Adapts fully follow the FNV1A implementation.

  • TETHASHV1 FNV1A implementation

Following are reference implementation of FNV1A adapted in TETHashV1.

// Reference Pseudo c/cpp implementation #define FNV_PRIME 0x01000193U #define FNV_OFFSET_BASIS 0x811c9dc5U #define fnv1a(x, y) ((((FNV_OFFSET_BASIS^(x))*FNV_PRIME) ^ (y)) * FNV_PRIME) #define fnv1a_reduce(a,b,c,d) (fnv1a(fnv1a(fnv1a(a, b), c), d))

Another Byte aligned implementation of FNV1A , call to FNV1c

#define FNV_PRIME 0x01000193U #define FNV_OFFSET_BASIS 0x811c9dc5U #define fnv1i(x) ( (( (( (( \ ( ((FNV_OFFSET_BASIS)^( ((x)>>24)&0x000000ff )) * FNV_PRIME) \ ^ (((x)>>16 )&0x000000ff)) * FNV_PRIME) \ ^ (((x)>>8 )&0x000000ff)) * FNV_PRIME) \ ^ (((x) )&0x000000ff)) * FNV_PRIME) \ ) #define fnv1c(x, y) ((fnv1i(x) ^ (y)) * FNV_PRIME)

5. FNV-Analysis

FNV Mix Algorithm Analysis for TEthashV1

How to test and analysis reference test code.

You can compile it with simple in terminal. No additional library needs,

gcc -o fnvtest fnvcltest.c

And You can execute it


F(00,00)::VEC(0, 0, ffffffff, 0)::      FNV  :00000000, DF=00000000(00) DS(00000000), FNV1 :00000000, DF=00000000(00) DS(00000000), FNV1a:117697cd, DF=117697cd(17) DS(117697cd), FNV1c:1210d00f, DF=127f8dbf(20) DS(11a1725f),         F___RC=efe1b9c4, DF:efe1b9c4(19) , F1__RC=deb68dfe, DF:deb68dfe(22) , F1A_RC=99bad28b, DF:99bad28b(17) , F1C_RC=e29fa497, DF:e29fa497(18)
F(00,01)::VEC(0, 1, ffffffff, 0)::      FNV  :00000001, DF=00000001(01) DS(00000001), FNV1 :01000193, DF=01000193(06) DS(01000193), FNV1a:1076963a, DF=010001f7(09) DS(01000193), FNV1c:1110ce7c, DF=03001e73(11) DS(01000193),         F___RC=fefffe6d, DF:111e47a9(14) , F1__RC=d9fd8597, DF:074b0869(12) , F1A_RC=72c287e0, DF:eb78556b(19) , F1C_RC=6b6991ef, DF:89f63578(17)
F(00,02)::VEC(0, 2, ffffffff, 0)::      FNV  :00000002, DF=00000003(02) DS(00000001), FNV1 :02000326, DF=030002b5(08) DS(01000193), FNV1a:0f7694a7, DF=1f00029d(11) DS(01000193), FNV1c:1410d335, DF=05001d49(09) DS(030004b9),         F___RC=d8fd8404, DF:26027a69(13) , F1__RC=9b16d24c, DF:42eb57db(19) , F1A_RC=c17f0ecb, DF:b3bd892b(18) , F1C_RC=a5be8e78, DF:ced71f97(21)
F(00,03)::VEC(0, 3, ffffffff, 0)::      FNV  :00000003, DF=00000001(01) DS(00000001), FNV1 :030004b9, DF=0100079f(10) DS(01000193), FNV1a:0e769314, DF=010007b3(09) DS(01000193), FNV1c:1310d1a2, DF=07000297(09) DS(01000193),         F___RC=b2fb099b, DF:6a068d9f(16) , F1__RC=5c301f01, DF:c726cd4d(17) , F1A_RC=94cf402e, DF:55b04ee5(16) , F1C_RC=aea1a025, DF:0b1f2e5d(17)
F(00,04)::VEC(0, 4, ffffffff, 0)::      FNV  :00000004, DF=00000007(03) DS(00000001), FNV1 :0400064c, DF=070002f5(10) DS(01000193), FNV1a:0d769181, DF=03000295(07) DS(01000193), FNV1c:0e10c9c3, DF=1d001861(09) DS(050007df),         F___RC=8cf88f32, DF:3e0386a9(14) , F1__RC=1d496bb6, DF:417974b7(17) , F1A_RC=89401d59, DF:1d8f5d77(20) , F1C_RC=e4e96c7c, DF:4a48cc59(13)
F(00,05)::VEC(0, 5, ffffffff, 0)::      FNV  :00000005, DF=00000001(01) DS(00000001), FNV1 :050007df, DF=01000193(06) DS(01000193), FNV1a:0c768fee, DF=01001e6f(11) DS(01000193), FNV1c:0d10c830, DF=030001f3(09) DS(01000193),         F___RC=66f614c9, DF:ea0e9bfb(20) , F1__RC=de62b86b, DF:c32bd3dd(19) , F1A_RC=346e222c, DF:bd2e3f75(21) , F1C_RC=502e5f82, DF:b4c733fe(20)
F(00,06)::VEC(0, 6, ffffffff, 0)::      FNV  :00000006, DF=00000003(02) DS(00000001), FNV1 :06000972, DF=03000ead(10) DS(01000193), FNV1a:0b768e5b, DF=070001b5(09) DS(01000193), FNV1c:1010cce9, DF=1d0004d9(10) DS(030004b9),         F___RC=40f39a60, DF:26058ea9(13) , F1__RC=9f7c0520, DF:411ebd4b(16) , F1A_RC=b376a527, DF:8718870b(13) , F1C_RC=1241a9a4, DF:426ff626(17)
F(00,07)::VEC(0, 7, ffffffff, 0)::      FNV  :00000007, DF=00000001(01) DS(00000001), FNV1 :07000b05, DF=01000277(08) DS(01000193), FNV1a:0a768cc8, DF=01000293(06) DS(01000193), FNV1c:0f10cb56, DF=1f0007bf(15) DS(01000193),         F___RC=1af11ff7, DF:5a028597(13) , F1__RC=609551d5, DF:ffe954f5(22) , F1A_RC=14293bea, DF:a75f9ecd(21) , F1C_RC=49d34bba, DF:5b92e21e(16)
F(00,08)::VEC(0, 8, ffffffff, 0)::      FNV  :00000008, DF=0000000f(04) DS(00000001), FNV1 :08000c98, DF=0f00079d(12) DS(01000193), FNV1a:09768b35, DF=030007fd(12) DS(01000193), FNV1c:1a10dca7, DF=150017f1(12) DS(0b001151),         F___RC=f4eea58e, DF:ee1fba79(21) , F1__RC=21ae9e8a, DF:413bcf5f(19) , F1A_RC=eeebb7a5, DF:fac28c4f(17) , F1C_RC=7da04f47, DF:347304fd(16)
F(00,09)::VEC(0, 9, ffffffff, 0)::      FNV  :00000009, DF=00000001(01) DS(00000001), FNV1 :09000e2b, DF=010002b3(07) DS(01000193), FNV1a:087689a2, DF=01000297(07) DS(01000193), FNV1c:1910db14, DF=030007b3(10) DS(01000193),         F___RC=ceec2b25, DF:3a028eab(14) , F1__RC=e2c7eb3f, DF:c36975b5(18) , F1A_RC=54e1aef8, DF:ba0a195d(15) , F1C_RC=d425e1af, DF:a985aee8(16)
F(00,0a)::VEC(0, a, ffffffff, 0)::      FNV  :0000000a, DF=00000003(02) DS(00000001), FNV1 :0a000fbe, DF=03000195(07) DS(01000193), FNV1a:0776880f, DF=0f0001ad(10) DS(01000193), FNV1c:1c10dfcd, DF=050004d9(08) DS(030004b9),         F___RC=a8e9b0bc, DF:66059b99(15) , F1__RC=a3e137f4, DF:4126dccb(15) , F1A_RC=213fcd63, DF:75de639b(20) , F1C_RC=7e1d2751, DF:aa38c6fe(18)
F(00,0b)::VEC(0, b, ffffffff, 0)::      FNV  :0000000b, DF=00000001(01) DS(00000001), FNV1 :0b001151, DF=01001eef(12) DS(01000193), FNV1a:0676867c, DF=01000e73(09) DS(01000193), FNV1c:1b10de3a, DF=070001f7(11) DS(01000193),         F___RC=82e73653, DF:2a0e86ef(16) , F1__RC=64fa84a9, DF:c71bb35d(19) , F1A_RC=5598ce46, DF:74a70325(14) , F1C_RC=6400c630, DF:1a1de161(14)
F(00,0c)::VEC(0, c, ffffffff, 0)::      FNV  :0000000c, DF=00000007(03) DS(00000001), FNV1 :0c0012e4, DF=070003b5(10) DS(01000193), FNV1a:057684e9, DF=03000295(07) DS(01000193), FNV1c:1610d65b, DF=0d000861(07) DS(050007df),         F___RC=5ce4bbea, DF:de038db9(17) , F1__RC=2613d15e, DF:42e955f7(18) , F1A_RC=6a220ff1, DF:3fbac1b7(20) , F1C_RC=6e781da4, DF:0a78db94(15)
F(00,0d)::VEC(0, d, ffffffff, 0)::      FNV  :0000000d, DF=00000001(01) DS(00000001), FNV1 :0d001477, DF=01000693(07) DS(01000193), FNV1a:04768356, DF=010007bf(11) DS(01000193), FNV1c:1510d4c8, DF=03000293(07) DS(01000193),         F___RC=36e24181, DF:6a06fa6b(17) , F1__RC=e72d1e13, DF:c13ecf4d(18) , F1A_RC=168d4944, DF:7caf46b5(19) , F1C_RC=65bbcfa1, DF:0bc3d205(13)
F(00,0e)::VEC(0, e, ffffffff, 0)::      FNV  :0000000e, DF=00000003(02) DS(00000001), FNV1 :0e00160a, DF=0300027d(09) DS(01000193), FNV1a:037681c3, DF=07000295(08) DS(01000193), FNV1c:1810d981, DF=0d000d49(09) DS(030004b9),         F___RC=10dfc718, DF:263d8699(15) , F1__RC=a8466ac8, DF:4f6b74db(20) , F1A_RC=93e667bf, DF:856b2efb(19) , F1C_RC=76f80ee3, DF:1343c142(11)
F(00,0f)::VEC(0, f, ffffffff, 0)::      FNV  :0000000f, DF=00000001(01) DS(00000001), FNV1 :0f00179d, DF=01000197(07) DS(01000193), FNV1a:02768030, DF=010001f3(08) DS(01000193), FNV1c:1710d7ee, DF=0f000e6f(13) DS(01000193),         F___RC=eadd4caf, DF:fa028bb7(17) , F1__RC=695fb77d, DF:c119ddb5(17) , F1A_RC=0f485682, DF:9cae313d(17) , F1C_RC=3667e8dc, DF:409fe63f(18)
F(00,10)::VEC(0, 10, ffffffff, 0)::     FNV  :00000010, DF=0000001f(05) DS(00000001), FNV1 :10001930, DF=1f000ead(13) DS(01000193), FNV1a:01767e9d, DF=0300fead(14) DS(01000193), FNV1c:0210b6df, DF=15006131(09) DS(1500210f),         F___RC=c4dad246, DF:2e079ee9(17) , F1__RC=2a790432, DF:4326b34f(16) , F1A_RC=d10adebd, DF:de42883f(16) , F1C_RC=1ce48e12, DF:2a8366ce(15)

F(00,01) : is input x,y

VEC(0, 1, ffffffff, 0) : is fnv_reduce input vector (a,b,c,d)

FNV :00000001, DF=00000001(01) DS(00000001) :

  • FNV(00,01) result is 00000001 ,
  • DF : is changed bitcounts, compared with previous outputs, in this case prev[00,00] current[00,01] input is 1bit changed, and output result 1bit changed.
  • DS : is distances of previous result and current result , ABS(prev_fnvresult,current_fnvresult).

** Basically, DF is higher is best on hash algorithm.

F___RC=fefffe6d, DF:111e47a9(14) : fnv_reduce = fnv(fnv(fnv(a,b),c),d) result is fefffe6d , and Different Bits counts are 14 bits.


In case of ethash algorithm, it can't prevent ASIC forever.

And, current ethash algorithm's FNV function is deprecated.

So, It needs to be upgraded and it will make current ethash based ASICs obsolete.

And current TETHASHV1 FNV1A implementation is based on most of ethash , which is verified for a long time.

Another propose of big differencing the Ethash algorithm need to crypto analysis for a long times and need to GPU code optimization times.

Verification and Optimization timeline Examples

original ethminer (2015) -> claymore optimized miner (2016) [1year]

genoil ethminer (2015) -> ethereum-mining/ethminer (2017) [2year]

Test Results::

Tethash miner has 2~3% of hashrate degrade on GPU, due to more core computation time.

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

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